Nizamuddin Khan

Oxygenation and carbonylation studies of some ruthenium(III) Schiff base complexes containing nitrogen and oxygen as donor atoms. II

Abstract Synthesis and characterization of a series of ruthenium(III) Schiff base complexes of the type [RuIIILXY] where L=Schiff base viz. bis(naphthaldehyde)-o-phenylenediimine (naphoph), bis(naphthaldehyde)ethylenediimine (naphen), bis(naphthaldehyde)propylenediimine (naphprop) and bis(naphthaldehyde)diethylenetriimine (naphdien); XCl and YCl imidazole (Im) or 2-methylimidazole (2-MeIm) are reported. Elemental analysis, conductivity and IR studies of the complexes suggest an octahedral geometry around ruthenium. Magnetic moments of the complexes indicate a single unpaired electron in a low spin d5 configuration. Oxygenation studies in DMF or THF solutions suggest the reversible binding of molecular oxygen to the ruthenium(III) complexes. EPR studies at liquid nitrogen temperature and UVVis measurements at room temperature support the formation of a Ru(IV) superoxo species [RuIVL(O2·.)−Y]. The EPR spectrum of the Ru(IV) superoxo complex at 77 K (g1 = 2.063, g2 = 2.047, g3 = 2.023) is consistent with the odd electron occupying a highly localized antibonding π* orbital of molecular oxygen. The reversible binding of O2 and CO has been carried out in DMF at 10, 25 and 40 °C. The complexes show discrimination against the binding of CO over O2 as evinced by values of KO2 and KCO in the complexes. The thermodynamic paramegers ΔH°, ΔG° and ΔS° for oxygenation and carbonylation reactions are evaluated.

Synthesis, characterisation, oxygenation and carbonylation of ruthenium(III) schiff base complexes

Abstract Some ruthenium(III) Schiff base complexes of the type [RuLXY] n where L = Schiff base namely, bis(α-hydroxyacetophenone)- o -phenylenediimine (α- acetop.oph), bis(2-hydroxy-4-methoxyacetophenone) - o -phenylenediimine (4-MeOacetop.oph), bis(α- hydroxyacetophenone)ethylenediimine (α-acetop.en), bis(2-hydroxy-4-methoxyacetophenone)ethylenediimine (4-MeOacetop.en), bis(α-hydroxyacetophenone) propylenediimine (α-acetop.prop), bis(2-hydroxy- 4-methoxyacetophenone)propylendiimine (4-MeOacetop.prop), bis(α-hydroxyacetophenone)diethylenetriimine (α-acetop.dien), bis(2-hydroxy-4-methoxyacetophenone) diethylenetriimine (4-MeOacetop.dien), n = −1 when X=Y=Cl − , n =0 when X=imidazole (Im), 2-methylimidazole (2-MeIm) and Y = Cl − were synthesised and characterised by physicochemical methods. The reversible binding of molecular oxygen as well as carbon monoxide was carried out in DMF. The complexes show discrimination against the binding of CO over molecular oxygen as evinced by the values of K O 2 and K CO in the complexes. The thermodynamic parameters ΔH°, ΔG°, ΔS° for the carbonylation and oxygenation reactions at 10, 25 and 40°C are evaluated.

Synthesis, characterization and solvent dependent reversible binding of carbon monoxide to Ru(III) Schiff base complexes

Abstract Ruthenium(III) Schiff base complexes of the composition [RuLXY] where L=Schiff base, viz. bis(salicylaldehyde)- o -phenylenediimine (saloph), bis(salicylaldehyde)ethylenediimine (salen), bis(salicylaldehyde)diethylenetriimine (saldien) bis(picolinaldehyde)- o -phenylenediimine (picoph), bis(picolinaldehyde)ethylenediimine (picen), bis(picolinaldehyde)diethylenetriimine (picdien); X=chloro(Cl − ); Y=chloro(Cl − ), imidazole (Im) or 2-methylimidazole (2-MeIm) were synthesized and characterized by various physicochemical methods. The reversible binding of carbon monoxide to the Ru(III) Schiff base complexes was carried out in DMF, CH 3 CN, CH 3 OH and CH 3 COCH 3 at 10, 25 and 40 °C. The polarity of the solvents as well as the electron donating subituents on Schiff base complexes increase the affinity of the complexes for CO. The thermodynamic parameters Δ H °, Δ G ° and Δ S ° for the carbonylation of Schiff base complexes were evaluated.